Circuit controlling mechanism



Oct. 18, 1938. J SCHM|D|NGER 2,133,309

CIRCUIT CONTROLLING MECHANISM Filed Jan. 12, 1937 2 Sheefs-Sheec 1 3? INVENTOR Joseph Schm idz'nger Oct. 18, 1938. J sc N ER 2,133,309

CIRCUIT CONTROLLING MECHANISM Filed Jan. 12, 1937 2 Sheets-Sheet 2 .1 -.E1 lNv z-:N ToR T 1 Joseph Schmzdmger ATTORNEYS switch device of the Patented a. 18, 1938 nmcnmsu Joseph si nings rm. N. Y. Application January 12, 1931, Serial N's-126,230

This invention relates thermo-responsive electric switch devices and particularly switch devices of the character set forth in my Patent No. 2,074,345, issued March 23, 1937.

One object of the invention is an improved above indicated character which is characterized by its simplicity in construction, its wearing endurance in operation and the economy with which it may be manufactured in large quantities.

Further-objects of the invention will hereinafter appear.

For a better understanding of the invention reference may be had to the accompanying drawings forming a part of this application wherein:

Fig. 1 is a diagrammatic side view of a device embodying one form of the invention;

' Fig. 2 is a diagrammatic side view of a device embodying another form of the invention;

Figs. 1a and 2a are enlarged diagrammatic views corresponding to Figs. 1 and 2 respectively illustrating thev operation thereof;

Fig. 3 is a diagrammatic side view of a device embodying another form of the invention;

Fig. 4 is a diagrammatic side-view of a device embodying another form of the invention;

Figs. 4a and 4b are enlarged diagrammatic side views indicating the operation of the device of Figs. 11 and 12 from one position to the other;

Fig. 5 is a plan view of an element of the devices of Figs. 1 to 4; and

Figs. 6, 7 and 8 are diagrammatic side views of further modifications.

Referring to the drawings, I have illustrated my;invention as embodying a control member 30 which is mounted and rigidly fastened at its ends to frame supports or parts II and 32, the

"at a point 36. adjacent the end distance between the parts 3| and 32 of the frame being less than the length of the control member 30 so as to cause the same to buckle, as illustrated in the drawings. This control member 30 has a portion 33 intermediate its ends of weaker and less rigid construction than other partsmf the member, and preferably, beginning 34, the control member 30 is gradually reduced in cross section to the point 33 and then gradually increased in The latter facilitates to the frame part 32,

stantially the same thickness but'gradually reduced in width to and from the narrowed weakened part 33.

' The are so set up iacent frame part ll and the control member mounted and fastened to each other as to a bias in that part of the member 30 adto the frame part II which bias tends at all times to cause the strip 30 to buckle laterally in one direction (upwardly as illustrated in the drawings) tening part 3 This may be effected by rigidly fasthe end 34 of the strip flat against the I and then forming a permanent set in the part 81 adjacent the frame part II, this part 31 being set at frame an angle to the surface of the part II against which the end of the strip is fastened. This is the preferred way of setting up the bias accomplishing this but any other suitable way of may be employed. In the embodiment of the drawings the frame part 32 is shown disposed parallel to and in the plane of the part II, and the end II of the strip .30 is fastened flat against the frame part 32, and the strip I to the frame rivetin A th 0 may be fastened in any suitable manner parts 3| and 82 as by welding, 8, etc.

ermo-responsive means is provided for operating the strip ll against the bias of the part 3'! and in the particular embodiment shown this means includes an expansible and contractable wire 40 whichis rigidly connected at one end to a frame part II and at its other end directly to the bias part 31 of the strip 30.

tening The latter fasconnection is formed by means of an element 42, in the partlcular embodiment shown a pin member, which is either formed of a part of the strip 30 or is welded or otherwise rigidly fastened thereto. operates the strip When the wire 40 is cold, it 30 against the bias formed therein to cause the strip to occupy one control positio n of equilibrium, and when the wire 40 is heated and thereby caused to expand the bias of the strip is permitted to cause the strip 30 to buckle into another control position of equilibrium.

curren from an electrical In the embodiment of The wire t passing 40 may be heated directly by therethrough or by radiation heater element.

Figs. 1 to '7 the wire is heated by current flowing directly therethrough,

while heated by a heater element 43 in the embodiment of Fig. 8 the wire is associated with the wire 40.

In the embodiment of Fig. 1 the two control positio of the tact ll byasl us of equilibrium of the strip 30 are deflned disposed on one side of the II disposed on the other side strip, the contact arm ll carrying the conbeing insulatedly carried from the frame eeve element 46. The stop I is preferably adjustable andthe adjustment may be effected in any suitable manner, this adjustment, being laterally of the strip. The wire Mi is insulatedly anchored'to the element iii of the frame in any suitable manner, but preferably by forming the element (it with an eyelet and a recess through which the wire it is threaded and fusing a glass bead ii? to the wire and causing the glass bead 38 to rest firmly within the seat of the recess-formed in ii. The tension of the wire id when cold may be adjusted by forming the element M of a bendable post, or the latter may be formed of abias in a direction to increase the tension on the wire 56; and a screw adjusti'ng means, indicated diagrammatically at 9, may be provided for overcoming the bias and lessening the tension on the wire id. The circuit to be controlled is indicated at its and a switch tit is indicated in that circuit. Upon closing the switch 563' the circuit is completed through the device as follows: wire 58, wire dd, pin 32, strip 3d, contact 3% on the strip 3%, contact 3 i, arm 16, and wire The wire (iii being cold the circuit is closed at the contacts and G6. The wire 6t, however, is heated by the current flowing therethrough thereby causing the same to expand and permitting the strip 3d uder its bias to be shifted to its other position of equilibrium, namely, against the stop at. The circuit now being broken the wire 15i cools OE and contracts and shifts the strip 363 to the closed position again, whereupon the wire dd is again heated to permit the opening of the circuit.

In the embodiment of Fig. 2 the contacts as and M are disposed across the wire instead of in series with the wire, with the result that when the contacts are closed the wire cools off and when the contacts are open the current passes throughthe wire it to heat it. When the switch 58 is closed the circuit is through wire 5!, frame part 32, strip 36, pin 52, wire fit, resistance wire fill, contact arm ll, outgoing wire 52.

By confining and restricting the lateral movement of the strip til to the comparatively short gap between the adjustable stop #35 and the contact 44, as shown in Figs. 1 and 2, certain ad- .vantages in construction and operation are obtained. It is observed that in both the opposite control positions of equilibrium the strip at assumes generally a buckled 8 form. Figs. 1a. and 2a, which correspond respectively to Figs. 1 and 2, are diagrammatically drawn to a larger scale to show generally the shape of this s form in the two opposite control positions and to also show intermediate positions in dot and dash lines, these intermediate positions illustrating generally the critical position when the strip 30 is on the point of being shifted over from one position to the other control position. For example, in Fig. 1a. the dot and dash curve corresponds to the position when the wire 40 has cooled down sufficiently to begin to buckle the strip 30 in opposition to its bias and the strip is just on the point of being shifted downwardly to bring the contact 39 into contact with the contact M. In Fig. 2a. the dot and dash curve corresponds to the position when the strip 30 is on the point of being shifted abruptly from the contact 44 to the full line position. In both instances a snap action is obtained in going from either opposite control position to the other and, moreover, there is obtained at the same time a wiping action between the contacts 44' and 39 as is shown generally in Fig. 2a. In Fig. 2a during the period of contraction two distinct actions of the congreases tacts occur. One is the shifting or rubbing action of contact 39 shown very clearly and a second action of importance is that the conact pressure is increased while the wire is moving two opposite control positions, namely, by adjusting the distance laterally of the strip between the stop 35 and the contact G5 in Fig. Either the contact 56' or the stop 65 may be adinstead or both may be adjusted, as, for example, by bending their supports. In the modification of Fig. 2 no lower stop for the strip 36 is required because the tension of the wire ts is insufhcient to buckle the strip all the way through.

The number of cycles may also be varied by varying the current supplied to the wire Qt or the heating resistance 53, since an increase of current how, other conditions being the same, would shorten the period the current is on the wire or heating coil and, conversely, a decrease of the current flow would lengthen the period the current is on.

The length of time required to shift from one control position to the other can be controlled by varying the tension of the expansible element. For example, by increasing the tension of the wire a higher temperature and consequenly a longer time is required to expand the wire surficiently to permit the bias of the strip 30 to throw it to the opposite control position; but this higher temperature of the wire required to shift the switch results in a more rapid dissipation of the heat during the period that the heating current is ofi, and accordingly by increasing the tension of the wire that period is decreased. With a decrease in tension of the wire, other conditions being the same, the reverse efiect is produced.

In the'modification of Fig. 3 no upper stop is provided for the strip 30 and the tension of the wire M1 is adjusted with respect to the bias of the strip 36 to cause the strip to buckle all the way through against the bias. In this case the contact arm 55 carrying the contact 55' is made of substantial resiliency so as to follow, as shown in dotted lines, the strip 30 to the critical point where the latter is on the point of being abruptly shifted over to the dotted position indicated by a snap action. The circuit of Fig. 3 corresponds to the circuit of Fig. 1.

The modification of Fig. 4 is similar to Fig. 3, except that the circuit of Fig. 2 is used wherein the cooling of the wire 40 results in the opening of the circuit at contacts 39 and 55'. The contact carrying arm 55 is also here resilient in order to follow the contact 39 in its downward movement to the critical point of the strip 30.

Figs. 4a and 4b illustrate generally the operation of the srip 30in going from one opposite control position to the other in the modification of Fig. 4. Fig. 40 indicates generally the opera tion of the strip 30 during the cooling of the wire 60, wherein the dotted position corresponds to the heated and expanded condition of the wire 30 to bring the contacts 39 and 55' together. 7 The closing of the contacts results in short circuiting ihe wire 40 which then cools rapidly and contracts, and the dot-dash line indicates generally the buckle of the strip 30 at the critical point,

namely. the instant when the strip II is ori-v the point of being'abruptly shifted downwardly with a snap action by the contact wire 4| against the bias of the strip ll. Fig. 4b shows generally the operation of the strip ll while the wire 4. is being heated. The full line position corresponds to the open circuit position oi the contacts 38 and II and to the cool condition of the wire 40. Since the current now passes through the wire or since the wire isheated by the current under the control of the contacts, the wire begins to heat up and to expand and the dot and dash curve indicates generally the shape and position of the buckling strip IO when it reaches thecritical poin, namely, when it is just on the point of being abruptly shifted over by a snap action by the bias of the strip to bring the contacts I9 and II together.

In the modification of Fig. 6 the frame parts II and I2 form a part of a plate or strip I. The stop 45 is carried by a bendable arm 45 which is rigidly fastened to the plate or strip 60, and by bending the arm 45' the stop I! may be adjusted up and down as may be desired. The lower contact 44' is insulatedly carried by a sleeve 6 I, which in turnis fastened to an arm 62, the latter is resilient and an adjusting screw 6'3 mounted in the plate 60 is provided for adjusting the arm 62 and the contact 44' against the bias of the arm 62 to any desired position. The circuit of Fig. 6 corresponds to the circuit of Fig. 1.

In the modification of Fig. 7 the upper contact 44' forms a stop and this contact is insulatedly carried by a sleeve 6i fastened to the arm 82. An adjusting screw 63 carried by the plate 60 adjusts the arm 62 against the bias thereof, the stop and contact 44 being thereby adjusted to any desired position.

The modification of Fig. 8 corresponds to that of Fig. l but here the wire is heated not directly by current passing therethrough. but by radiation from a heater 3 associated therewith and connected in the circuit to be controlled by the contacts 44' and 38.

I claim:

1. In a device of the character described, the combination comprising a constrained member 01' spring material operative to different positions of equilibrium and rigidly fixed at both ends and constrained to cause it to tend to assume one of said positions, a limiting stop which the member engages when free, said constrained member having a portion intermediate its ends of weaker construction than the portion adjacent oneend, the latter portion being adapted to be flexed in opposition to the inherent constraint of the member to cause the same to become disengaged from the stop and to assume a second position of equilibrium, thermo-responsive means connected with the said second named portion of the said constrained member and adapted under certain conditions to fiex the same and cause it to assume the last named position of equilibrium, and means for altering the temperature of the said thermo-responsive means.

2. In a device of the character described, the combination comprising a constrained member of spring material operative to different positions of equilibrium and rigidly fixed at both ends and constrained to cause it to tend to assume one of the said positions, a limiting stop which the member engages when free, the said constrained member being a portion intermediate its ends of weaker construction than the portion adjacent one end, the latter portion being adapted to be tened to the said last named portion, thermoresponsive means connected with the said element and adapted under certain conditions to.

engages when free, the said member having a portion adjacent to one end biased to cause the said part to tend to assume one of said positions of equilibrium but adapted to be flexed in opposition to the inherent bias thereof to cause the said part to become disengaged from the stop and to assume a second position of equi-- librium, thermo-responsive means connected with said biased portion and adapted under certain conditions to flex the same and to cause the said part to assume the last named position of equi-- librium, and means for altering the temperature of the said thermo-responsive means, the said member oi spring material being of progressively diminishing strength from the said biased portion to the said part.

4. In a device of the character described, the combination comprising a constrained buckling member of spring material operative to different positions of equilibrium and rigidly fixed at both ends and constrained to cause it to tend to assume one of 'said positions, a limiting stop disposed in the path of the buckling strip and arresting the buckling a second position of equilibrium, thermo-responsive means connected with the said second named portion of the said constrained member and perature of the said thermo-responsive means.

5. In a device of the character set forth in claim 1 wherein the stop engages the constrained member at a point adjacent the weaker portion thereof.

6. In a device of the character set forth in claim 1 wherein an electrical contact is disposed on the opposite side of said member from said stop.

7. In a device or the character set forth in claim 1 wherein said stop constitutes an electrical contact.

8. In a device 01' the character set forth in claim 1 wherein said stop constitutes an electrical contact and the thermo-responsive means includes an expansible wire which when cold flexes the member to cause the weaker portion thereof to snap away from said contact.

9. A circuit controlling device of the character set forth comprising a frame element, an elongated spring buckling strip element having both ill of its ends fastened flat against plane surfaces of said frame element, said surfaces extending generally in co-planar relation with said strip, the latter being longer than the distance loe-= tween said plane fastening surfaces and adapted to be buckled laterally from one position to another, said strip having a resilient bias formed in a part adjacent one end thereof tending to cause the strip to buckle in one direction, a therrno-responsive device connected with said biased part of the strip and adapted when cold to buckle said strip in opposition to the bias thereof to shift it in the other direction and electric contacts controlled by said strip.

10. in a device of the character set forth in claim wherein a stop is provided on one side to limit the buckling movement of the strip in that direction.

ll. In a device of the character set forth in claim 9 wherein a stop is provided on one side to limit the buckling movement oi the strip in that direction, and a contact is provided which is engaged by said strip in one position thereof.

12. in a device or the character set forth in claim 9 wherein a contact which is controlled by said strip is resiliently mounted and the strip is caused to be buckled all the way through from one extreme position to the other.

13. In a device of the character set forth in claim s wherein a stop is provided on one side to limit the buckling movement of the strip in that direction, said stop being adiustably mounted.

14. In a device of the character set forth in claim 9 wherein a stop is provided on one side to limit the buckling movement or the strip in that direction, and a contact is provided on the other side which limits the buckling movement in that arsaaoo direction, said contact and stop being relatively adjustable toward and away from each other.

15. A circuit controlling device of the character set forth, comprising a frame, an elongated spring buckling strip element having both of its ends rigidly fastened to the frame, the said strip being longer than the distance between the points of fastening and being inherently constrained to cause the same to buckle in one direction, a thermal responsive device operatively connected with said strip and adapted to buckle the same in opposition to the inherent constraint thereof to shift it in the other direction and electrical contacts controlled by said strip including a stop for arresting said strip in either or two controlled positions with the strip ass a generally s-hucizle form in both positions.

16. A device of the chmacter set iorth comprising a spring strip rigidly fastened at both ends and constrained to cause the same to huclrle, with means for arresting the buckling action to cause the strip to assume a generally a buckled form, and thermo-resnonsive means for actuating said strip against the inherent constraint thereof.

17. A device of the character set forth com= prising a spring strip rigidly fastened at looth ends and constrained to cause the some to buckle, with means for arresting the buckling action to cause the strip to assume a generally e buckled form, and thermo-responsive means for actuating said strip against the inherent constraint thereof, and means for adjusting the arresting means.

JOSEPH sonrmrnona. 

